Cost of microvascular complications in people with diabetes from a public healthcare perspective: a retrospective database study in Brazil

Figures & data

Table 1. ICD-10 diagnosis codes and frequency in patients with diabetes who experienced a microvascular complication (N = 2,096).

	Condition	ICD-10 code(s)	n (%)
Diabetes type	Insulin-dependent	E10, E10.0, E10.2, E10.3, E10.4, E10.5, E10.6, E10.7, E10.8, E10.9	632 (30.2)
	Non-insulin-dependent	E11, E11.0, E11.1, E11.2, E11.3, E11.4, E11.5, E11.6, E11.7, E11.8, E11.9	230 (11.0)
	Unspecified	E14, E14.0, E14.1, E14.2, E14.3, E14.4, E14.5, E14.6, E14.7, E14.8, E14.9	1,234 (58.9)
Microvascular complication	Diabetic foot including ulcer	L97	191 (8.4)
	Eye disease and diabetic retinopathy	H28.0, H36.0	117 (5.2)
	Kidney disease	N00.0, N00.3, N00.4, N00.8, N00.9, N03, N10, N11, N11.8, N11.9, N12, N15.8, N15.9, N16.3, N17, N17.0, N17.1, N17.8, N17.9, N18, N18.0, N18.8, N18.9, N19, Z49.1, Z94.0, Z99.2	1,667 (73.4)
	Neuropathy	G58.9, G59.0, G62.9, G63.2, M14.6	28 (1.2)
	Other microvascular	R02	267 (11.8)
	PVD	I78.9	0 (0.0)

Abbreviations. ICD-10, International Classification of Diseases, 10th Revision; PVD, peripheral vascular disease.

The denominator in the percentage calculations is 2,096 (the study cohort) for “diabetes type” and 2,270 (the qualifying number of microvascular complications) for “microvascular complications”. In total, 1,937 patients (92.4% of the study cohort), 145 (6.9%), 13 (0.6%), and 1 (0.0%) experienced 1, 2, 3, and 4 qualifying microvascular complications for study entry, respectively.

Figure 1. Patient flow diagram. The overall study cohort included patients enrolled in DATASUS with evidence of diabetes and a microvascular complication during the study period who did not meet any exclusion criteria. ^†Defined as ≥1 record with an accepted ICD-10 diagnosis code for diabetes (Table 1); ^‡defined as ≥1 record with an accepted ICD-10 diagnosis code for a microvascular (Table 1) or macrovascular (Table S1) complication; ^§defined as ≥1 record with an accepted ICD-10 diagnosis code for a macrovascular complication (Table S1). Abbreviations. DATASUS, Ministry of Health’s Information Technology Department; ICD-10, International Classification of Diseases, 10th Revision.

Table 2. Age distribution of patients with diabetes who experienced a microvascular complication (N = 2,096).

Microvascular complication	n	Age at index date, years
		Mean ± SD	Median [IQR]	Minimum–maximum
Kidney disease	1,667	65.4 ± 14.8	66.0 [57.0; 76.0]	12.0–103.0
Other microvascular	269	67.8 ± 12.6	68.0 [59.0; 76.0]	27.0–99.0
Diabetic foot including ulcer	191	68.3 ± 12.1	69.0 [60.0; 76.5]	30.0–97.0
Eye disease and diabetic retinopathy	117	59.6 ± 13.1	60.0 [55.0; 69.0]	25.0–85.0
Neuropathy	28	62.7 ± 13.2	65.0 [55.0; 71.3]	30.0–81.0

ICD-10: International Classification of Diseases, 10th Revision; IQR: interquartile range; n: number of patients that contributed to data point; SD: standard deviation.

The month of the qualifying microvascular complication was defined as the index date.

Table 3. Direct medical costs in patients with diabetes who experienced a microvascular complication, overall and stratified by gender.

Cohort	Time period	n	Direct medical cost, 2019 USD
			Mean ± SD	95% CI	Median [IQR]	Minimum–maximum
Overall (N = 2,096)	Baseline −1	975	310.2 ± 860.0	256.1; 364.2	113.7 [90.7; 236.8]	0.0–10,865.4
	Baseline	1,600	668.3 ± 1,438.7	597.7; 738.8	176.3 [91.0; 481.2]	0.0–15,940.0
	First year	2,096	3,425.1 ± 3,358.0	3,281.3; 3,569.0	1,678.5 [287.0; 6,908.4]	0.0–18,026.2
	Second year	1,178	4,261.6 ± 3,485.5	4,062.4; 4,460.9	5,172.4 [274.8; 7,395.9]	0.0–17,490.2
	Third year	943	3,674.0 ± 3,515.2	3,449.4; 3,898.7	2,525.4 [167.0; 7,311.5]	0.0–16,953.1
Female (n = 1,006)	Baseline −1	504	353.4 ± 1,007.2	265.2; 441.5	116.0 [90.7; 247.2]	0.0–10,865.4
	Baseline	776	757.2 ± 1,622.8	642.9; 871.6	181.4 [93.0; 535.6]	0.0–15,940.0
	First year	1,006	3,597.0 ± 3,383.7	3,387.6; 3,806.3	2,233.8 [306.6; 6,974.7]	0.0–18,026.2
	Second year	595	4,163.7 ± 3,441.4	3,886.6; 4,440.8	4,802.8 [277.6; 7,337.5]	0.0–15,454.9
	Third year	465	3,707.4 ± 3,548.4	3,384.1; 4,030.8	2,605.3 [154.0; 7,343.5]	0.0–11,286.5
Male (n = 1,090)	Baseline −1	471	263.9 ± 665.5	203.7; 324.2	110.9 [90.7; 222.6]	0.0–7,758.8
	Baseline	824	584.5 ± 1,235.8	500.0; 669.0	172.2 [91.0; 459.3]	0.0–15,596.3
	First year	1,090	3,266.5 ± 3,327.8	3,068.8; 3,464.3	1,324.7 [261.9; 6,868.8]	0.0–13,532.9
	Second year	583	4,361.6 ± 3,530.2	4,074.5; 4,648.8	5,553.8 [266.6; 7,446.9]	0.0–17,490.2
	Third year	478	3,641.5 ± 3,486.0	3,328.2; 3,954.9	2,444.9 [186.0; 7,298.0]	0.0–16,953.1

Abbreviations. CI, confidence interval; n: number of patients that contributed to data; IQR, interquartile range; SD, standard deviation; USD, United States dollars.

Baseline corresponds to the year before the qualifying complication, while baseline −1 refers to the year before baseline (i.e. between 1 and 2 years before the qualifying complication). First, second, and third year refer to the respective year after the qualifying complication. Costs were weighted by patient observation time using an annual general standardization.

Figure 2. Associations between demographic and clinical characteristics with the incurrence of high direct medical costs in patients with diabetes who experienced a microvascular complication (N = 2,096). Data are odds ratio [95% CI] for associations between parameters and high direct medical costs (defined as the highest tertile of annual cost data ranked by median cost for patients in the overall study cohort) from binary logistic regression modeling. Square brackets in the first column indicate the reference category. Baseline corresponds to the year before the qualifying complication, while first and second year refers to the respective year after the qualifying complication. Abbreviation. CI, confidence interval.

Table 4. Length of hospital stay in patients who experienced a microvascular complication, overall and stratified by gender.

Cohort	Time period	n	Length of hospital stay per patient, days
			Mean ± SD	Median [IQR]	Minimum–maximum
Overall (N = 2,096)	Baseline −1	758	4.2 ± 14.0	0.0 [0.0; 4.0]	0.0–316.0
	Baseline	1,204	6.5 ± 16.7	2.0 [0.0; 8.0]	0.0–523.0
	First year	2,096	8.8 ± 15.7	3.0 [0.0; 11.0]	0.0–179.0
	Second year	472	3.4 ± 17.8	0.0 [0.0; 0.0]	0.0–546.0
	Third year	432	2.8 ± 12.0	0.0 [0.0; 0.0]	0.0–342.0
Female (n = 1,006)	Baseline −1	386	4.7 ± 16.4	0.0 [0.0; 4.0]	0.0–316.0
	Baseline	570	7.1 ± 21.4	2.0 [0.0; 8.0]	0.0–523.0
	First year	1,006	8.5 ± 15.7	3.0 [0.0; 10.0]	0.0–179.0
	Second year	229	3.1 ± 18.7	0.0 [0.0; 0.0]	0.0–546.0
	Third year	214	2.8 ± 13.3	0.0 [0.0; 0.0]	0.0–342.0
Male (n = 1,090)	Baseline −1	372	3.6 ± 11.1	0.0 [0.0; 3.0]	0.0–219.0
	Baseline	634	6.0 ± 10.8	2.0 [0.0; 8.0]	0.0–155.0
	First year	1,090	9.1 ± 15.6	3.0 [0.0; 12.0]	0.0–154.0
	Second year	243	3.6 ± 16.9	0.0 [0.0; 0.0]	0.0–320.0
	Third year	218	2.8 ± 10.8	0.0 [0.0; 0.0]	0.0–181.0

Abbreviations. n, number of patients that contributed to data point; IQR, interquartile range; SD, standard deviation.

Baseline corresponds to the year before the qualifying complication, while baseline −1 refers to the year before baseline (i.e. between 1 and 2 years before the qualifying complication). First, second, and third year refer to the respective year after the qualifying complication. Costs were weighted by patient observation time using an annual general standardization.

Table 5. Direct medical costs for the ten most frequent medical procedures and medications for patients with diabetes who experienced a microvascular complication (N = 2,096).

Description	n	Total annual direct medical cost, 2019 USD
Medical procedures
Associated with kidney complications
Hemodialysis (≤3 sessions per week)	1,203	2,043,407.2
Confection of arteriovenous fistula for hemodialysis	699	16,711.6
Long-term catheter implant for hemodialysis	450	16,622.3
Post-transplant follow-up (kidney, liver, heart, lung, hematopoietic stem cells, and/or pancreas transplant)	34	3,672.5
Associated with peripheral vascular disease
Finger amputation/disarticulation	370	8,541.2
Amputation/disarticulation of lower members	318	20,308.1
Associated with diabetes, other microvascular complications and other
Treatment of diabetes mellitus	1,595	83,914.2
Treatment of complicated diabetic foot	579	15,878.6
Maintenance and household accompanying of patients	175	207,546.2
Home hospitalization	26	5,322.2
Medications
Associated with kidney complications
Ferric hydroxide saccharate 100 mg injectable (per 5 mL bottle)	649	3,759.0
Epoetin alfa 4,000 IU injectable (per bottle)	628	901.7
Calcitriol 0.25 mcg (per capsule)	248	770.9
Sevelamer 800 mg (per pill)	273	347.2
Calcitriol 1.0 mcg injectable (per ampoule)	99	443.6
Epoetin alfa 3,000 IU injectable (per bottle)	89	1,474.9
Epoetin alfa 2,000 IU injectable (per bottle)	62	48.4
Sodium mycophenolate 360 mg (per pill)	27	0.0
Associated with other microvascular complications
Atorvastatin 20 mg (per pill)	36	0.0
Atorvastatin 10 mg (per pill)	23	0.0

Abbreviations. IU, international units; n, number of patients that contributed to data point; SUS, Sistema Único de Saúde (the Brazilian public health system).

Data presented are total annual direct medical costs (2019 United States dollars) across patients (with the stated procedure or medication) over the study period, both before and after the qualifying complication. Costs were weighted by patient observation time using an annual general standardization. Procedures and medications were defined as per the SUS table of procedures, medications and orthoses, prostheses, and special materials [24].

DataSUS. The SUS table of procedures, medications and orthoses, prostheses and special materials (OPM) (SIGTAP); 2019 [cited 2021 Feb]. Available from: http://www.sgc.goias.gov.br/upload/links/arq_961_tabelacompleta.pdf

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Data availability statement

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.